1. Technical Field
With reference to FIG. 1, a typical analog modem system is presented. A modem 102 connects to another modem 104 via telephone lines 106 to transmit and receive information. In order for the modems to communicate with each other, each modem must first determine the type of modem with which it is attempting to communicate, in order to, inter alia, transmit data at an optimum rate.
More particularly, with reference to FIG. 4, a typical connection between a data client 402 and the Internet 422 is depicted. Data client 402 is typically a computer that is coupled to a modem 404. In order to connect to the Internet 422, data client 402 is coupled to an Internet Service Provider (“ISP”) 420. Point of presence 410 is used to interface between ISP 420 and modem 404. Located within point of presence 410 is a remote access server (“RAS”) 412 that contains a central site modem 414. Central site modem 414 is coupled to an IP cloud 418 that sends and receives data, in packet form, to and from ISP 420. RAS 412 is also coupled to an information server 416 that serves to control RAS 412.
Data traditionally follows a path from modem 404, through the public switched telephone network (“PSTN”) 408, to point of presence 410. RAS 412 (within point of presence 410) sends and receives data, in packet form, through IP cloud 418 to ISP 420, thereby connecting data client 402 to the Internet 422.
There may be situations in which ISP 420 does not own or control point of presence 410, but rather contracts with, e.g., a regional service provider that owns or controls point of presence 410. In this situation, the regional service provider may be paid on the basis of call connection percentage. Therefore, it would be desirable for the regional service provider to be able to diagnose problems on the telephone lines to improve the call connection percentage. It may be necessary to gather information from modem 404 in order to gather the appropriate data. However, there is no means within point of presence 410 that would enable the gathering of such information. It would be desirable to establish a private data channel between modem 404 and information server 416 in order to gather such data.
For a number of reasons, it may also be desirable to enable one modem device to identify itself to another modem device during the modem initialization process such that, if the devices are compatible with each other, a number of enhanced features can be prompted or employed. The use of such differentiated features may allow certain compatible modem devices to operate in an improved manner, relative to incompatible modem devices. However, the standard handshake sequences used by two modem devices to establish communications have only a limited capability to exchange manufacturer-specific information for system identification, configuration, and diagnostics.
The conventional V.8bis handshake sequence provides some capability to exchange system-specific information during the initial handshake procedure. For example, some modem manufacturers use the V.8bis handshake sequence to exchange limited diagnostic and identification information. This exchange is only available at the beginning of a call, however, because manufacturers generally do not wish to prolong the handshake sequence. Using the handshake sequence to exchange diagnostic and identification information is generally undesirable, as the user would be forced to wait longer for a connection to be established. In addition, during the handshake sequence, data is being transmitted at a relatively low rate because, until the modems determine the type of modem with which it is communicating, the modems cannot transmit at their maximum speed. Therefore, it may not be desirable to transmit a large amount of data before the handshaking sequence is completed and a data channel is opened that operates at a faster speed.
The manner in which the modem devices exchange the identification data and the type of data exchanged can be varied to address a number of practical issues, e.g., improved performance at a central site ISP location; improved diagnostic information available to the central site ISP location; as well as differentiated features that may be developed in the future. The performance associated with a central site may be related to the number of unintentional call disconnections, the number of calls that progress beyond the initial handshaking procedure, the data rates obtained during the connections, and other functional aspects of the modem connections established through the central site.
During the handshaking procedure, while it may be desirable to exchange as much information as possible for diagnostic and identification reasons, such an exchange should consider the duration of the handshake sequence: it is typically undesirable to significantly lengthen the duration of the handshake sequence. Furthermore, the transmission of diagnostic data and identification information should be transparent to the user. In addition, it is desirable to identify the client modem very early in the handshake sequence so that the central site modem is can capture information and utilize the information to help diagnose and address connectivity problems in the field. It is thus desirable for a modem to have a short handshake period along with full-featured end-to-end diagnostics. It would be desirable to enhance the ability of the modem devices to exchange such information, without burdening the initial handshake and thereby delaying the time needed to establish a connection. In addition, it may be desirable to establish a communications channel between modem devices that is available throughout the call, not just at the beginning of the call. Furthermore, it may also be desirable for modem devices to be able to compare diagnostic information from a previous connection with diagnostic information from a connection between the same devices at a later time.